1// Copyright 2014 The Go Authors. All rights reserved. 2// Use of this source code is governed by a BSD-style 3// license that can be found in the LICENSE file. 4 5//go:build dragonfly || freebsd || linux || netbsd || openbsd 6// +build dragonfly freebsd linux netbsd openbsd 7 8package unix 9 10import "unsafe" 11 12// fcntl64Syscall is usually SYS_FCNTL, but is overridden on 32-bit Linux 13// systems by fcntl_linux_32bit.go to be SYS_FCNTL64. 14var fcntl64Syscall uintptr = SYS_FCNTL 15 16func fcntl(fd int, cmd, arg int) (int, error) { 17 valptr, _, errno := Syscall(fcntl64Syscall, uintptr(fd), uintptr(cmd), uintptr(arg)) 18 var err error 19 if errno != 0 { 20 err = errno 21 } 22 return int(valptr), err 23} 24 25// FcntlInt performs a fcntl syscall on fd with the provided command and argument. 26func FcntlInt(fd uintptr, cmd, arg int) (int, error) { 27 return fcntl(int(fd), cmd, arg) 28} 29 30// FcntlFlock performs a fcntl syscall for the F_GETLK, F_SETLK or F_SETLKW command. 31func FcntlFlock(fd uintptr, cmd int, lk *Flock_t) error { 32 _, _, errno := Syscall(fcntl64Syscall, fd, uintptr(cmd), uintptr(unsafe.Pointer(lk))) 33 if errno == 0 { 34 return nil 35 } 36 return errno 37} 38